Core Vocabulary Official Included By Default

This vocabulary defines JSON Schema core terminology and mechanisms; related specifications build upon this specification and define different applications of JSON Schema.

Dialect Draft 3
URI https://json-schema.org/draft-03/draft-zyp-json-schema-03.pdf
Specification https://json-schema.org/draft-03/draft-zyp-json-schema-03.pdf
Authors
Metaschema http://json-schema.org/draft-03/schema#

This vocabulary is mandatory on this dialect. It is available by default and cannot be removed.

Keywords

Keyword Kind Instance Summary
id Identifier Any This keyword declares an identifier for the schema resource.
$schema Identifier Any This keyword is both used as a JSON Schema dialect identifier and as a reference to a JSON Schema which describes the set of valid schemas written for this particular dialect.
$ref Applicator Any This keyword is used to reference a statically identified schema.
extends Applicator Any Validation succeeds if the instance is valid against the schema or schemas defined by this keyword
type Assertion Any Validation succeeds if the type of the instance matches the type represented by the given type, or matches at least one of the given types.
disallow Assertion Any Validation succeeds if the type of the instance does not match the type represented by the given type, or does not match at least one of the given types.
properties Applicator Object Validation succeeds if, for each name that appears in both the instance and as a name within this keyword’s value, the child instance for that name successfully validates against the corresponding schema.
patternProperties Applicator Object Validation succeeds if, for each instance name that matches any regular expressions that appear as a property name in this keyword’s value, the child instance for that name successfully validates against each schema that corresponds to a matching regular expression.
additionalProperties Applicator Object Validation succeeds if the schema validates against each value not matched by other object applicators in this vocabulary. If set to a boolean, no additional properties are allowed in the instance.
items Applicator Array If set to a schema, validation succeeds if each element of the instance validates against it. If set to an array, validation succeeds if each element of the instance validates against the schema at the same position, if any.
additionalItems Applicator Array If items is set to an array of schemas, validation succeeds if each element of the instance not covered by it validates against this schema. If set to a boolean, no additional items are allowed in the array instance.
minItems Assertion Array An array instance is valid if its size is greater than, or equal to, the value of this keyword.
maxItems Assertion Array An array instance is valid if its size is less than, or equal to, the value of this keyword.
uniqueItems Assertion Array If this keyword is set to the boolean value true, the instance validates successfully if all of its elements are unique.
required Assertion Object An object instance is valid if the name of the required property exists in the instance.
dependencies Assertion Object Validation succeeds if, for each name that appears in both the instance and as a name within this keyword’s value, either every item in the corresponding array is also the name of a property in the instance or the corresponding subschema successfully evaluates against the instance.
enum Assertion Any Validation succeeds if the instance is equal to one of the elements in this keyword’s array value.
pattern Assertion String A string instance is considered valid if the regular expression matches the instance successfully.
minLength Assertion String A string instance is valid against this keyword if its length is greater than, or equal to, the value of this keyword.
maxLength Assertion String A string instance is valid against this keyword if its length is less than, or equal to, the value of this keyword.
divisibleBy Assertion Number A numeric instance is valid only if division by this keyword’s value results in an integer.
minimum Assertion Number Validation succeeds if the numeric instance is greater than, or equal to, the given number, depending on the value of exclusiveMinimum, if any.
exclusiveMinimum Assertion Number When minimum is present and this keyword is set to true, the numeric instance must be greater than the value in minimum.
maximum Assertion Number Validation succeeds if the numeric instance is less than, or equal to, the given number, depending on the value of exclusiveMaximum, if any.
exclusiveMaximum Assertion Number Validation succeeds if the numeric instance is less than the given number.
format Annotation String Define semantic information about a string instance.
description Annotation Any An explanation about the purpose of the instance described by the schema.
title Annotation Any A preferably short description about the purpose of the instance described by the schema.
default Annotation Any This keyword can be used to supply a default JSON value associated with a particular schema.